Hello All,
I hope someone can help me out a little bit. Does any one know the electrical characteristics of the cylinder head temperature sensor ? As in what is the resistance range over a given temperature range ? I know the resistance goes down as the temperature goes up. Also, as the temperature increases, does this sensor enrich or derich the fuel mixture ? I am looking to bias my sensor a little to try and correct a wicked rich condition. Thanks for any info you may have.

I don't remember the resistance values off the top of my head...

The resistance drops as it heats up (thermistor). It's designed for enrichment when themotor is cold. So as the engine heats up, and the resistance drops, the ECU leans out the mixture. A common "patch" is to place a 270 ohm resistor in-line with the HTS to richen the mixture up a little.

-Josh2

here you go....

L-Jet troubleshooting and info

Josh and Mueller,
Outstanding, Thanks for the help. Using the web location, I was able to build a profile for the sensor, then model different resistances both in series (enriches mixture) as well as parallel (leans out mixture). Sorry, Electrical Engineer peeking out again 270 ohms is some serious enrichment. Again, thanks for the help, and I will post the results of some testing I will do on playing with the resistances.

Check w/ Drewvw He's done some resistor modification along the lines that you are talking about.

-pt

If you have a "wicked rich condition" on an AFC car, it's almost always a bad airbox. The CHT isn't gonna be involved once the engine is fully warmed up. You might also check the fuel pressure and the operating voltage, but my money's on the airbox.

The Cap'n

[quote name='Cap'n Krusty' date='Aug 17 2006, 05:32 PM' post='754493']
[quote name='mnementh' post='753786' date='Aug 16 2006, 05:50 PM']

If you have a "wicked rich condition" on an AFC car, it's almost always a bad airbox.
[/quote]


A bad airbox, like not sealing correctly?

OK. All good info, because I am currently on a steep learning curve. I will check out the air box and see what is going on there. Thanks a lot for the help.

[quote name='ptravnic' date='Aug 17 2006, 07:28 PM' post='754715']
[quote name='Cap'n Krusty' date='Aug 17 2006, 05:32 PM' post='754493']
[quote name='mnementh' post='753786' date='Aug 16 2006, 05:50 PM']

If you have a "wicked rich condition" on an AFC car, it's almost always a bad airbox.
[/quote]


A bad airbox, like not sealing correctly?
[/quote]

Like, "broken", either electronically or physically. L-jet 1.8s have an airbox, more properly called an "airflow meter", and they go bad, generally resulting in a exceedingly rich condition. They're car specific, meaning the '74 takes one, the 75 another, and they fit no other car (well, except the 74 T4, but where are you ever gonna find parts for one of those?). The reman units are a notorious waste of time and money, especially thiose from "Bret". Royze's aren't any good, either. New ones are basically NLA. Good luck, The Cap'n

BTW, reading through the other posts, it appears some folks think your car is D-jet, and consequently are telling you stuff that doesn't even apply to your car.

Cap'n,
I appreciate the input. I noticed that some of the info above was related to the D-Jet as well, but still appreciate the guys trying to help. I will use the troubleshooting guide on the link that Mueller provided and meter out the air box. I was looking inside it last night, and there appears to be a couple of grooves worn in the carbon track. Again, Thanks for the help.

L-jet was used on many other cars. Go junkyard shopping and retune one from another car.

does the vane move easily without sticking?

b